As a person ages, airway patency may be reduced due to loss of muscle tone in the muscles of the throat which normally serve to prevent the tissues from impinging on the airway. This condition is more severe in patients who are obese, have naturally narrow airways or airways that may be partially blocked by tonsils, soft palate or uvula. The result can be snoring as the tissues vibrate as air is forced through the narrowed airway under heightened pressure. Snoring is disruptive to sleep; the snorer not only keeps companions awake but will himself awaken many times in the night. This sleep disturbance leads to a feeling of tiredness or exhaustion during the day and a decrease in mental and physical performance.
In about a third of snorers, the condition can be lethal. When narrowing of the airway proceeds to complete occlusion, the condition is termed sleep apnea. A faulty feedback loop between the brain and the respiratory system lets the airway completely collapse until the brain registers low oxygen levels and the patient jerks awake to resume breathing. These constant jump starts, which can happen as often as once a minute, send the heart rate on a roller coaster. In susceptible patients, high heart rates can bring on fatal arrhythmia or myocardial infarction.
Continuous positive airway pressure (CPAP) is a method in use for some time to alleviate the symptoms of snoring or sleep apnea by delivering air or gas under a pressure sufficient to mimic the effect of the natural waking tone of the throat muscles in holding the soft tissues around the airway from partially or totally occluding the airway passage. Patients other than those with airway problems can benefit from CPAP. These groups include patients with weakened respiratory muscles who cannot pull air into their lungs, such as those with post polio or amyotrophic lateral sclerosis disease, patients with traumatic nerve damage or adult respiratory distress. CPAP apparati are generally comprised of a blower for providing a stream of air or gas under pressure, a mask and tubing to connect the mask to the blower source. The mask can cover both the mouth and nose, the nose alone, or have plugs that insert only into the nares. Whatever the configuration, the mask must have, as a minimum, a means of sealing the mask to the face so that the blower gas does not escape, thereby reducing the pressure to the airway. Vents must be provided for exhaled gases. Preferably the vents are placed so as to avoid the eyes of the patient. A mask support is necessary to hold the mask and tubing in proper apposition.
Patient compliance is often a problem. Many of the masks currently available are uncomfortable, tend to be dislodged during sleep or disconnected from the blower source. If the mask is a full face mask covering both nose and mouth or a nasal mask covering only the nose, the peripheries of the mask will touch the bridge of the nose, the upper or lower lip and must seal around the malar region. Individual variations in the topography, especially of the malar region, make it necessary to hold the mask to the face with some pressure. It has been shown that a double seal, with a semirigid internal support and a flexible skirt can be inflated with air, forming a seal that more readily conforms to the malar region. The ideal mask support is usable with any variety of full face or nasal mask to accommodate individual needs and preferences.
The mask support must be capable of holding the mask firmly in position with as low a pressure as possible to avoid irritation of the face, especially the bridge of the nose. A popular design comprises a rigid band cantilevered over the medial line of the skull, with the blower source tubing arranged and secured along the band. (U.S. Pat. Nos. 1,081,745 and 6,347,631.) The only points at which the support applies pressure to the patient are at the occipital lobe and the mask.
The need remains for a face mask support that is comfortable, does not apply pressure to small or sensitive areas of the head and is not easily dislodged or disconnected from its blower source.